/* $OpenBSD: readpass.c,v 1.51 2015/12/11 00:20:04 mmcc Exp $ */
/*
 * Copyright (c) 2001 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"
#include "xmalloc.h"
#include "misc.h"
// #include "pathnames.h"
#include "log.h"
// #include "ssh.h"
// #include "uidswap.h"
#import <UIKit/UIKit.h>

extern __thread char *ssh_progname;

/* private/internal read_passphrase flags */
#define RP_ASK_PERMISSION    0x8000 /* pass hint to askpass for confirm UI */


/*
 * Reads a passphrase from /dev/tty with echo turned off/on.  Returns the
 * passphrase (allocated with xmalloc).  Exits if EOF is encountered. If
 * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
 * tty is available
 */
char *
read_passphrase(const char *prompt, int flags)
{
    char cr = '\r', *askpass = NULL, *ret, buf[1024];
    int rppflags, ttyfd, use_askpass = 0, allow_askpass = 0;
    const char *askpass_hint = NULL;
    const char *s;

#if !TARGET_OS_IPHONE // askpass is not going to work here.
    if ((s = getenv("DISPLAY")) != NULL)
        allow_askpass = *s != '\0';
    if ((s = getenv(SSH_ASKPASS_REQUIRE_ENV)) != NULL) {
        if (strcasecmp(s, "force") == 0) {
            use_askpass = 1;
            allow_askpass = 1;
        } else if (strcasecmp(s, "prefer") == 0)
            use_askpass = allow_askpass;
        else if (strcasecmp(s, "never") == 0)
            allow_askpass = 0;
    }
#endif
    
    rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
#if !TARGET_OS_IPHONE // askpass is not going to work here.
    if (use_askpass)
        debug_f("requested to askpass");
    else if (flags & RP_USE_ASKPASS)
        use_askpass = 1;
    else if (flags & RP_ALLOW_STDIN) {
        if (!isatty(STDIN_FILENO)) {
            debug("read_passphrase: stdin is not a tty");
            use_askpass = 1;
        }
    } else {
        rppflags |= RPP_REQUIRE_TTY;
        ttyfd = open(_PATH_TTY, O_RDWR);
        if (ttyfd >= 0) {
            /*
             * If we're on a tty, ensure that show the prompt at
             * the beginning of the line. This will hopefully
             * clobber any password characters the user has
             * optimistically typed before echo is disabled.
             */
            (void)write(ttyfd, &cr, 1);
            close(ttyfd);
        } else {
            debug("read_passphrase: can't open %s: %s", _PATH_TTY,
                strerror(errno));
            use_askpass = 1;
        }
    }

    if ((flags & RP_USE_ASKPASS) && !allow_askpass)
        return (flags & RP_ALLOW_EOF) ? NULL : xstrdup("");

    if (use_askpass && allow_askpass) {
        if (getenv(SSH_ASKPASS_ENV))
            askpass = getenv(SSH_ASKPASS_ENV);
        else
            askpass = _PATH_SSH_ASKPASS_DEFAULT;
        if ((flags & RP_ASK_PERMISSION) != 0)
            askpass_hint = "confirm";
        if ((ret = ssh_askpass(askpass, prompt, askpass_hint)) == NULL)
            if (!(flags & RP_ALLOW_EOF))
                return xstrdup("");
        return ret;
    }
#endif
    
    if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) {
        if (flags & RP_ALLOW_EOF)
            return NULL;
        return xstrdup("");
    }

    ret = xstrdup(buf);
    explicit_bzero(buf, sizeof(buf));
    return ret;
}

int
ask_permission(const char *fmt, ...)
{
    va_list args;
    char *p, prompt[1024];
    int allowed = 0;

    va_start(args, fmt);
    vsnprintf(prompt, sizeof(prompt), fmt, args);
    va_end(args);

#if !TARGET_OS_IPHONE
    p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF|RP_ASK_PERMISSION);
#else
    p = read_passphrase(prompt, RP_ECHO);
#endif
    if (p != NULL) {
        /*
         * Accept empty responses and responses consisting
         * of the word "yes" as affirmative.
         */
        if (*p == '\0' || *p == '\n' ||
            strcasecmp(p, "yes") == 0)
            allowed = 1;
        free(p);
    }

    return (allowed);
}


static void
writemsg(const char *msg)
{
	(void)write(STDERR_FILENO, "\r", 1);
	(void)write(STDERR_FILENO, msg, strlen(msg));
	(void)write(STDERR_FILENO, "\r\n", 2);
}

struct notifier_ctx {
	pid_t pid;
	void (*osigchld)(int);
};

struct notifier_ctx *
notify_start(int force_askpass, const char *fmt, ...)
{
	va_list args;
	char *prompt = NULL;
	pid_t pid = -1;
	void (*osigchld)(int) = NULL;
	const char *askpass, *s;
	struct notifier_ctx *ret = NULL;

	va_start(args, fmt);
	xvasprintf(&prompt, fmt, args);
	va_end(args);

	if (fflush(NULL) != 0)
		error_f("fflush: %s", strerror(errno));
	if (!force_askpass && isatty(STDERR_FILENO)) {
		writemsg(prompt);
		goto out_ctx;
	}
#if TARGET_OS_IPHONE
	writemsg(prompt);
    fflush(thread_stderr);
#else
	if ((askpass = getenv("SSH_ASKPASS")) == NULL)
		askpass = _PATH_SSH_ASKPASS_DEFAULT;
	if (*askpass == '\0') {
		debug3_f("cannot notify: no askpass");
		goto out;
	}
	if (getenv("DISPLAY") == NULL &&
	    ((s = getenv(SSH_ASKPASS_REQUIRE_ENV)) == NULL ||
	    strcmp(s, "force") != 0)) {
		debug3_f("cannot notify: no display");
		goto out;
	}
	osigchld = ssh_signal(SIGCHLD, SIG_DFL);
	if ((pid = fork()) == -1) {
		error_f("fork: %s", strerror(errno));
		ssh_signal(SIGCHLD, osigchld);
		free(prompt);
		return NULL;
	}
	if (pid == 0) {
		if (stdfd_devnull(1, 1, 0) == -1)
			fatal_f("stdfd_devnull failed");
		closefrom(STDERR_FILENO + 1);
		setenv("SSH_ASKPASS_PROMPT", "none", 1); /* hint to UI */
		execlp(askpass, askpass, prompt, (char *)NULL);
		error_f("exec(%s): %s", askpass, strerror(errno));
		_exit(1);
		/* NOTREACHED */
	}
#endif
 out_ctx:
	if ((ret = calloc(1, sizeof(*ret))) == NULL) {
		kill(pid, SIGTERM);
		fatal_f("calloc failed");
	}
	ret->pid = pid;
	ret->osigchld = osigchld;
 out:
	free(prompt);
	return ret;
}

void
notify_complete(struct notifier_ctx *ctx, const char *fmt, ...)
{
	int ret;
	char *msg = NULL;
	va_list args;

	if (ctx != NULL && fmt != NULL && ctx->pid == -1) {
		/*
		 * notify_start wrote to stderr, so send conclusion message
		 * there too
		*/
		va_start(args, fmt);
		xvasprintf(&msg, fmt, args);
		va_end(args);
		writemsg(msg);
		free(msg);
	}

	if (ctx == NULL || ctx->pid <= 0) {
		free(ctx);
		return;
	}
#if !TARGET_OS_IPHONE
	kill(ctx->pid, SIGTERM);
	while ((ret = waitpid(ctx->pid, NULL, 0)) == -1) {
		if (errno != EINTR)
			break;
	}
	if (ret == -1)
		fatal_f("waitpid: %s", strerror(errno));
	ssh_signal(SIGCHLD, ctx->osigchld);
#endif
	free(ctx);
}
